1. Field of the Invention
The present invention relates to a latching relay, and, in particular, to a latching relay having a manual reset function.
2. Description of the Related Art
A latching relay of the prior art as shown in FIG. 1 includes switch 10 and coil 12. The on/off states of the latching relay are controlled by the current flowing through coil 12. Once the latching relay maintains an on or off stable state, the current flowing through coil 12 can be switched off until the state of the latching relay is required to change. However, when the latching relay employed for power control is in an off-state, resulting in a power down, the current can not flow through coil 12, whereupon the state of switch 10 can not be changed. At this point, the power can be temporarily supplied to coil 12 by using one-shot voltage control switch 14, such that the latching relay can be brought into an on-state.
Currently, the above-mentioned latching relay is widely used. However, since the latching relay can not be switched to an on-state in a power down situation, the latching relay can not be used in a wired telephone or power controller. Generally, the latching relay in a wired telephone is used to force a wired telephone into an on-hook (off-line) state. Since the power can not be provided to the coil after the telephone is on-hook, the latching relay can not be reset. Likewise, the same problem happens in the power controller. Thus there is typically an additional one-shot voltage control switch used to restart the power.